Title : o-Phenylenediamine as a New Catalyst in the Highly Regioselective Conversion of Epoxides to Halohydrins with Elemental Halogens ( o-Phenylenediamine as a New Catalyst in the Highly Regioselective Conversion of Epoxides to Halohydrins with Elemental Halogens )

The regioselective ring opening of epoxides using elemental iodine and bromine in the
presence of o-phenylenediamine as a new catalyst affords vicinal iodo alcohols and bromo alcohols in
high yields. The major advantages of this method are versatility, high regioselectivity, a cheap and
commercially available catalyst, mild and neutral reaction conditions, and short reaction times. Fourier
transform Raman spectroscopy was used to study the reaction of iodine with o-phenylenediamine. The
results indicate that the complex [(Diamine)I]þ I5
is formed, and we suggest that the major nucleophile
is the pentaiodide ion. This bulky nucleophile has a fundamental role in the high regioselectivity
observed attacking the less sterically hindered epoxide carbon.